It says my battle.net tag is missing or invalid. I've tried /oq harddrop then /reload and it doesn't work.

Please check what version you are running. The current version is oQueue 1.8.8b

Also check that you are connect to Battle.net while in the game

Open your friends list and look at the top of your friends list.

Does your friends list at the top say: "Set your broadcast:", or does it show your battletag?